1. Technical Field
The subject matter discussed herein relates to systems and methods for link fate sharing in multi-router configurations.
2. Description of the Related Art
In communication networks throughout the world, communication traffic is increasing exponentially. Network service providers must constantly upgrade and improve their network infrastructures to compensate for the ever-increasing volume of communication traffic. To transport data across long distances, network links are provided between large metropolitan areas, for example, over a backbone network. One way to compensate for the increase in traffic volume is to add routers at gateways in the metropolitan areas. This can increase the available bandwidth between cities by using similarly sized routers without having to replace existing routers. This has the effect of forming parallel network links between different locations. Because of the way routers typically operate, such parallel configurations can have undesirable consequences if one or more of the links fail.
Network routers share information about the status of links in the network. Interior gateway protocol (IGP) is one example of a protocol for sharing network link information. When Open Shortest Path First (OSPF) or similar protocols are used, routers generally choose the lowest cost link route. If the lowest cost link fails, the routers use the next lowest cost alternative route to avoid the failed link. In parallel configurations, where there are multiple links between pairs of cities, if one of the links fails, routers may begin forcing traffic that would have normally traversed the failed link onto the remaining operational links between the cities.
The remaining operational links can thereby be overwhelmed. For example, in a two-link parallel configuration, if a link fails, all the traffic from the failed link will suddenly be routed onto the remaining functional link. Such a situation effectively eliminates any benefit the extra link provided.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the invention is to be bound.